BSA Project 92

Bruce Main-Smith, The First Classic BSA Scene, Bruce Main-Smith Pub. 1982

The BSA Project 92 was a last ditch effort by Norton Villiers Triumph to sell a single cylinder street motorcycle. Using a frame of the aborted BSA Fury, the 500cc B50 pushrod engine was mounted using Isolastic-type mounts. Using what was available in the parts bins, Norton tank, seat and dual mufflers were fitted. The bike was developed in 1971-72 but was not proceeded with. 

Someone was paying attention though, a few years later Yamaha released the SR500 alongside their new XT500.

 I see online this motorcycle was also considered to be a Norton P92.